Wildfire-Atmosphere Interaction Index for Extreme Fire behaviour

During the last 20 years extreme wildfires have challenged firefighting capabilities. Often, the prediction of the extreme behaviour is essential for the safety of citizens and fire fighters. Currently, there are several fire danger indices routinely used by firefighting services, but they are not suited to forecast convective extreme wildfire behaviour at global scale. This article proposes a new fire danger index, extreme fire behaviour index (EFBI), based on the analysis of the vertical profiles of the atmosphere above wildfires as an alternative to the use of traditional fire danger indices. The EFBI evaluates the ease of interaction between wildfires and the atmosphere that could lead to convective, erratic and extreme wildfires. Results of this research in the analysis of some of the critical fires in the last years show that the EFBI can potentially be used to provide valuable information to identify convective fires and to enhance fire danger rating schemes worldwide.

A comparative study on the rheological properties of coal water slurries using sodium tripoly-phosphate and carboxy-methyl-cellulose as dispersants

The effects of two anionic dispersants (polymeric-carboxy methyl cellulose: CMC and inorganic-sodium tripolyphosphate: STPP) on the rheological properties of coal water slurries (CWS) of varying solid loading were reported and compared. The rheological data was obtained in the shear rate range of 60-160 s^-1 and the data was fitted using power law model. For lower solid concentrations (10% and 20%), shear thickening behaviour was observed while shear thinning nature was seen for the higher solid loadings (30%,40% and 50%) for CWS with both the dispersants. For all slurries, an increase in flow behaviour index values was seen with the increase of dispersant loading. For CWS of 10% and 20% solid loadings, lower values of flow behaviour index was observed with CMC as dispersant. On the other hand, lower values for flow behaviour index was seen with STPP as dispersant for CWS of 30%, 40% and 50% solids loading. Although CMC was found very effective in reducing the apparent viscosity at lower dosages unlike STPP, the apparent viscosity values are quite sensitive to the loading of CMC as dispersant in comparison to STPP. This observed trend may be due to aggressively induced negative charges upon the adsorption of CMC on coal particles at the tested dispersant dosages.

A new eco-friendly and low cost additive in water based drilling fluids

This study investigates the possibility of using rice husk ash as an additive to develop an environmentally friendly and low-cost drilling fluid system. The rice husk ash was added as an additive to water-based bentonite drilling fluids at different concentrations ranging from 2 wt% to 15 wt%. Rheological and filtration properties of each drilling fluid developed were measured by using a viscometer and standard low-pressure low-temperature filter press. Subsequently, cutting carrying index, minimum annulus velocity required to clean bottom of the well efficiently, flow behaviour index and permeability of mud cakes of the formulated systems were calculated in order to assess performance of the systems. The results demonstrated that the rheological and properties were improved depending on concentration of rice husk ash introduced. With the introduction of 15 wt% concentration of rice husk ash, while apparent viscosity and yield point increased by 60% and 183%, respectively, thixotropy and plastic viscosity decreased by 29% and 63%, respectively. On the other hand, drilling fluid with 4% wt% content of rice husk ash reduced the fluid loss by 10%. Moreover, results showed that cutting carrying index, minimum annulus velocity required to clean bottom of the well efficiently and flow behaviour index of the enhanced with the exploitation of rice husk ash in the drilling fluid. This study showed that rice husk ash as a promising additive to use in the water-based bentonite drilling fluids when properly implemented, and hence reducing the impact on the environment, and the total cost for drilling.

Analysis of entrepreneurial behaviour of women farmers in Abia State, Nigeria

This study analysed entrepreneurial behaviour of women farmers in Abia state, Nigeria. Multi-stage random sampling method was used to select 120 women farmers from whom data were collected using structured questionnaire. Descriptive statistics, entrepreneurial behaviour index and ordinary least square (OLS) regression technique were used to analyse data. Results showed that mean age, household size, farming experience and farm size of the women farmers were 44 years, 6 persons, 16 years and 0.6 hectares respectively. Mean entrepreneurial behaviour index of the women farmers was 44.34. The OLS regression result with double-log as lead equation posted an R2 value of 0.6392 and revealed that age, educational level, extension contact, farm income, membership to cooperative society and profit motive were significant determinants of entrepreneurial behaviour of women farmers. Majority of the women farmers had high input cost, difficulty in getting loan, land procurement issues and lack of requisite support from research institutions as constraints to their entrepreneurial engagements. The study recommends that state and local governments should make policies and establish programmes that will promote entrepreneurial skills of women farmers, curb unemployment and alleviate poverty among women. Keywords: Behaviour index, entrepreneurial behaviour, entrepreneurship, women farmers

Physicochemical, pasting, and rheological properties of pearl millet starches from different cultivars and their relations

Physicochemical, pasting, and rheological properties of pearl millet starches were studied and correlations among these properties were calculated. Amylose content, swelling power, and solubility of starches varied from 11.57 to 21.93%, 11.11 to 17.91 g g−1 and 12.20 to 15.20%, respectively. Volume% of starch granule size less than 10 µm varied from 36.23 to 48.34%, and 12.16 to 18.75% for above 20 µm size of granule. Peak viscosity of starches varied from 1291 to 1853 mPa·s, cv. RHB-173 had the highest value. Frequency sweep measurement of starch pastes revealed higher magnitude of G′ as compared to G″ with increase in to, indicating visco-elastic behaviour. Yield stress (σo), consistency index (K), and flow behaviour index (n) were observed as 40.73 to 115.72 Pa, 0.729 to 3.998 Pa·s, and 0.604 to 0.964, respectively. Starch pastes from cultivars studied showed shear thinning behaviour.